My training partners and I have been having on on going debate stemming from an article I was told authored by Mark Twight. I would like to start out by saying that we are both big into the Paleo diet when training and more of a zone style when not training as hard. We are getting ready for an extreme endurance test performed over three weeks and we have been going back and forth over the use of "powergels" vs just nuts and water. One idea was brought up over the use of soy protein in this mix vs whey (like in my favorite Zone bars). I do not fully understand why soy would be better and further do not know about where is the best way to obtain an easy delivery system of soy - please help if you can - Thank you,
Just nuts and water will yield quite a slow pace and declining recovery on a day-to-day basis when stretched over long-term endurance type stress. Gels and other carbs are essential, especially for recovery, as is noted in the Paleo Diet for Athletes. In any case, by the end of week two, if you've been going hard and digging deep you'll probably be eating whatever is in the way ... and that's when you'll figure out what really works. Until then it's all theoretical.
"Science-diet" type foods are not necessarily essential to the type of effort you describe but they are convenient, and they allow you to control delivery of particular nutrients. Since you'll likely be in calorie deficit the entire time you can mitigate the degree of performance decline by getting more calories using fuels designed specifically for the purpose.
Regarding protein, prophylactic protein intake reduces muscle catabolism and speeds recovery. When intensity permits, 10-15% of the calories eaten during long-term effort should be from protein sources. Do not eat excessive protein, when the amino acids are broken down they produce ammonia.
To (help) avoid ammonia production use soy protein for prophylactic supplementation instead of whey (for more info on this check out the May 2007 edition of Hammer Nutrition's Endurance News, which you should find a link to on the Hammer Nutrition site). There are positives and negatives to using soy. Do the research to decide if it's worth it. I think it is. Other supplements to counteract ammonia production are available, and used by some, but the basics start with preventing the breakdown of muscle tissue.
Endurance fuels containing small quantities of protein are worth looking at: Spiz and Perpetuem in particular. There may be some others but I don't have personal experience with them. You can also mix your own "science-diet" type fuels to provide the exact ratios of component parts your experimentation has told you works best for you, i.e. buy maltodextrin powder, soy or whey or rice protein (from a clean source), flavoring, etc. and build a meal-replacement drink to complement whatever "real" food you plan to or can eat.
Eating while moving is pace-dependent, the higher the work intensity the less "complicated" the food may be.
There's a lot to learn and hopefully this answer will cause you to ask more questions, and begin looking under all of the many rocks out there to find clues that will help. It's a long road ...